Pyrometric element



June 17, 1941. A. EEKROGH PYROMETRIC ELEMENT Filed Nov. 13, 1936 INVENTOR. ANKER a KROGH ATTORNEY Patented June 17, 1941 UNITED STATES PATENT OFFICE PYROMETRIC ELEMENT Anker E. Krogh, Philadelphia, Pa., assignor to The Brown Instrument Company, Philadelphia.

Pa., a corporation of Pennsylvania Application November 13, 1936, Serial No. 110,600

8 Claims.

The general object of the present invention is to provide improved apparatus for use in measuring a furnace temperature with a radiation py-' rometer, and the invention comprises a pyrometric furnace wall element of refractory material, adapted to be incorporated in the wall of a furnace chamber, and having a well extending into the element from the side of the. latter at the outer side of said wall and having a relatively thin well end wall portion separating the well space from the chamber, said well being adapted to receive a portion of a radiation pyrometer by which the temperature of said thin wall portion may be measured.

With the said element formed of silicon-carbide or analogous refractory material adapted to withstand high temperatures, and preferably having relatively good heat conductivity .when heated, the heat radiation from the outer side of the wall portion of the element between the pyrometer well and the furnace chamber, provides a good indication of the temperature within the portion of the furnace chamber from which heat is radiated against the adjacent side of said portion. The saidelement provides protection for the pyrometer inserted in the well, against an objectionably large transfer of heat to said pyrometer portion and against injurious contact therewith of furnace chamber gases.

The improved pyrometric element is well adapted for use in the roof or crown of an open hearth furnace, and in such case, the element may advantageously be given the external configuration or shape needed to permit the element to serve as the keystone portion of a corresponding section of the furnace chamber roof. Under certain conditions of use, which are normal rather than abnormal, the furnace chamber side of the pyrometric element is subject to relatively rapid deterioration and burns, crumbles,

or wastes away, and a specific object of the present invention, is to prolong the effective life of the element by forming the latter so that the bottom wall of the pyrometer well may be renewed. To this end, the element is advantageously formed so that an inner portion of the pyrometer well, in the element in the original .form of the latter increases in cross section from its inner well end outward, and provides seats at decreasing distances from the outer end of the well, for disc-like parts of increasing size. In consequence, as the inner side of the element wastes away, first one and then another of said parts may be seated in the element to form the partition wall between the pyrometer well and the set of wall forming discs provided for successive use in the element as its inner side wastes away.

formed well end wall members in the body portion of the pyrometric element, each such member may be formed with a socket or projection part, or have a wire part imbedded therein, for detachable engagement by a hook or other implement which for use in manipulating the member and adjusting it into proper seating relation with the wall surrounding the inner portion of the well.

For a better understanding of the nature of the invention and specific objects and advantages attained with its use, reference should be had to the accompanying drawing and descriptive matter in which I have illustrated and described:

or the drawing:

Fig. 1 .is a sectional elevation of a portion of the roof or crown of a furnace chamber, incor porating a pyrometric element provided in accordance with the present invention;

Fig. 21s a sectional elevation, taken similarly to Fig. 1, and showing a pyrometric element of difierent form;

Figs. 3 and 4 are sections taken similarly to Fig. 2, illustrating the condition of the pyrometric element of Fig. 2 in successive later stages of its eflective life;

Fig. 5 is a plan view of a partition wall disc having engagement provisions of one form;

Fig. 6 is a section on the line 6-6 of Fig. 5;

Figs. 7, 8, and 9 are sections, each showing a partition disc, differing from the others in respect to its engagement provisions;

Fig. 10 is a plan view of a disc having engage- I ment provisions of still another form; and

Fig. 11 is a section on the line l|-Il of Fig. 10. In Fig. 1, A represents a portion of the crown or roof of the furnace chamber of an open hearth or analogous furnace, incorporating a pyrometric element provided in accordance with the present invention. Said element, as shown in Fig. 1,

comprises body portion B formed with a pyrometer well B open at its outer end, but closed at its inner end by an integral wall portion B. As shown, the element B has oppositely tapered To facilitate the mounting of the separately sides 3', to enable it to serve as a keystone portion of theseetion of the wall Ain which it is incorporated.

An outer end portion of the well B is cylindrical, and larger in diameter than the inner portion of the well, thus providing an annular shoulder 13 at the adJacent ends of the two portions. As shown, a portion of a radiation pyrometer G ex-- tends into the well B and substantially fills the cylindrical outer portion of the well. The pyrometer C may be of any usual or suitable form and, as shown, comprises a water cooled tubular portion extending into the well.

The portion of the well B at the inner side of the shoulder B is in the form of a truncated cone with its large diameter end adjacent the shoulder 13. Adjacent longitudinal sections of the inner wall of the conical inner portion of the well, are thus adapted to serve as seats for disc parts b, b, b, b, shown in dotted lines in Fig. 1, which progressively increase in cross section.

In the contemplated use of the element B, shown in-l'ig. 1, it is initially incorporated in the furnace wall with none of the discs, b, b", b, and lb in place, and may then have its furnace chamber end flushwith the furnace chamber side A of the wall A. For its intended use, the well side of the wall portion 13 of the element must attain a temperature approximating the temperature of the side of that wall portion exposed to the furnace chamber, so that the radiation pyrometer can provide a suitably accurate indication of the furnace chamber temperature. The said wall portion B is necessarily relatively thin, therefore, and because of its thinness, and the high temperature which it attains when the furnace chamber is high, the wall portion-B wastes away and is rendered inoperative, if not totally destroyed, after a relatively sort period of use, and while the outer portion of the element is still in good condition. when this occurs, one of the discs, b, b, b and b, is seated in the conical p rtion of the well as shown in dotted lines in Fig. 1, after punching out or breaking away the remaining portion of the initial inegral wall part B, when necessary to properly expose the furnace chamber side of the inserted disc to heat absorption from the furnace chamber. Ordinarily, the disc first inserted in the wall, will be the smaller one, D, of the series of discs. when, after a further period of use, the first disc part inserted wastes away and is no longer adapted to provide a proper heat conducting closure or inner end wall of the pyrometer well, another and larger disc is inserted in the well, and this replacement of one disc by another of larger size, maybe repeated as necessary.

As previously indicated, the body portion of the element andthe disc parts b, b, b", and b are advantageously formed of silicon-carbide, or

of some other available refractory material adapted to withstand the temperature and other conditions of use, and preferably having considerable heat conductivity, when highly heated, as such heat conductivity contributes to the maintenance of desirable partition disc temperature conditions and also, of itself, tends to prolong the life of the body and disc portions of the pyrometric element. Normally, and as shown, each disc part is in the form of a short truncated cone, the conical taper of the peripheral edge of which corresponding to that of the wall of the conical inner portion of the well.

In lieu of initially forming the pyrometric element with an integral well end wall portion 3, as shown in Fig. 1, the element may comprise a body portion BA, as shown in Figs. 2, 3, and 4, initially formed with a through passage which is converted into a pyrometer well like that of the element 13, by inserting a part like the disc b of Pig. 1, in the through passage preparatory to the initial.use of the element. As the innernend portion of the element BA including the disc I: originally inserted, wastes away, first one, and then another, of discs of progressively increasing size are put into use, as previously described in connection with Fig. 1. Fig. 2 shows the element BA with a partition b in place and in the form in which the element is originally put into use, and Figs. 3 and 4 show the same element in successive stages of its life, in which discs b and b are respectively in use. Under conditions of use with extremely high temperatures a larger disc than actually necessary may be insertedin the element, thereby removing the bottom wall portion thus formed, further from the furnace chamber and providing protection for the wall portion by virtue of the surrounding element walls.-

In the condition of the element BA shown in Figs. 3 and 4, the disc 17 or b may be said to separate the pyrometer well from an aligned inner well B The last mentioned well will normally be created inthe use of the pyrometric element, whether the latter is initially of the form shown in the Fig. 1 or of the form shown in Fig. 2, since the tendency to deterioration and wasting away of the element at its furnace chamber side is most pronounced at the periphery of the portion of the element extending across and forming the end wall of the pyrometer well. Figs. 3 and 4 are illustrative of the pyrometric element in later stages of its life, whether the element is initially of the form shown in Fig. 2 or of the form shown in Fig. 1.

With either of the elements 13 and BA, a new closure or end wall' for the inner end of the pyrometer well may be formed by dropping the appropriate disc into place through the outer end of the well, if the element is incorporated in the roof wall of the furnace chamber as is usual. To facilitate the proper seating of each disc part in the well, however, regardless of whether that well is or is not vertically disposed as shown in the drawing, each disc part may have provisions for detachable engagement by a, suitable implement used in moving the disc into proper seating relation with the wall B of the conical inner end portion of the well.

the disc part, in the process of manufacture of the latter. .80 formed, the disc part b' may be lowered into place by a manipulating element in the form of a wire hook E engaging the bail part D in the seating operation, and disengaged from the part b after the latter is seated. If desired, the outer side of the bail may be flush with the outer side of the disc part, as in the. case of the disc part b shown in Fig. 7 which is provided at its outer side with a recess b, across which the bail D' extends and into which the hook element, E may be inserted. The disc part b shown in Fig. 8, is provided with a central undercut button-like portion b surrounded by an annular recess, b formed in the outer side of the disc part b", so thatthe button or projection 21' may be engaged by a tong or plier-like manip-F ulating element F. In Fig. 9, the disc part b is formed with a centrally threaded socket b" in its outer side, to receive the threaded end of a manipulating rod G, which can be rotated to screw it out of the disc part I), after the latter is properly seated in the body portion of the pyrometric element in which it is used. In the arrangement shown in Figs. 10 and 11, the disc part b is formed at its outer side with a keyhole slot b in a wall covering a chamber or space b formed in the disc part, so that the latter may be operatively engaged by a manipulating rod element H formed with projections H received in the space b, during the manipulating operation. After the disc part b is seated, a partial turn of the rod H relative to the disc part} will bring the projections H into register with the narrow end portions of the keyhole slot b", and the rod may then be detached from the disc part.

As will be apparent to those skilled in the art, other provisions than those illustrated may be employed to facilitate the seating of a disc part in the body portion of a pyrometric element constructed in accordance with the present invention,

and while Figs. 1 to 4 illustrate what is now regarded as the preferred general form of embodiment of my invention, it will be apparent that changes in the form of said element may be made without departing from the spirit of my inventions as set forth in the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A pyrometric element of refractory material adapted to be incorporated in the wall of a furnace chamber and having a well extending into the element from the side thereof which is outermost when the element is incorporated in said wall, and having a portion of the wall of said well at a distance from said side shaped to provide seats at different distances from said side, each adapted to receive a corresponding separately formed part of refractory material forming a relatively thin wall between the well space at the outer side of the seat and said chamber, the outer end portion of said well being adapted to pass heat rays to a radiation pyrometer for measuring the temperature of said thin wall.

2. A pyrometric element of refractory material adapted to be incorporated in the wall of a furnace chamber and having a well extending into the element from the side thereof which is outermost when the element is incorporated in said wall, and means for establishing a thin end wall of refractory material for said well separating the well space from the furnace chamber and located at a distance from the said side of the element which may be successively diminished as the furnace chamber side of the element deteriorates in use.

3. A pyrometric element ofrefractory material adapted to be incorporated in the wall of a furnace chamber and formed with a weii extending into the element from the side thereof remote from the furnace chamber when incorporated in said wall, and having an inner end portion of said well shaped to provide seats at different distances from said side for successively usable well end wall parts, one such part being seated in the corresponding seat and separating the well space at the outer side of said part from the furnace chamber in any operative condition of the element, whereby as said element is rendered inoperative by the successive deterioration of its furnace chamber side it may be restored to operato pass heat rays to a radiation pyrometer measuring the temperature of the said part of said 10 element.

4. A pyrometric element of refractory material adapted to be incorporated in the wall of a furnace chamber and formed with a well extending into the element from the side thereof remote 15 from the furnace chamber when incorporated in said wall and having an inner end portion of i said well in the form of a truncated section of a cone having its apex at the furnace chamber side of the element so that different longitudinal sections of the wall surrounding said well portion forms seats for successively usable differently sizedend wall parts each in the form, of a short truncated conical section, one such part being seated in the corresponding seat and separating the well space at the outer side of said part from the furnace chamber in any operative condition of the element, whereby as said element is rendered inoperative by the successive deterioration of its furnace chamber side it may be restored to operative condition by the replacement of the one of said parts previously in use by another and larger one of said parts, the outer portion of said well being adapted to pass heat rays-etc a radiation pyrometer measuring the temperature of the said part of said element.

5. A pyrometric element of refractory material adapted to be incorporated in the wall of a furnace chamber an having a well extending into the element from the side thereof which is outermost when the element is incorporated in said ,wall, and having a portion of the wall of said well at a distance from said side shaped to provide seats at different distances from said side,

' each adapted to receive a corresponding separately formed part of refractory material forming a relatively thin wall between the well space at the outer side of the seat and said chamber, the outer end portion of said well being adapted to pass heat rays to a radiation py ometer for measuring the temperature of said thin wall, one such part being normally seated in the corresponding part and having an engagement portion at its outer side adapted for engagement by a manipulating element. a

6. A pyrometric element of refractory material adapted to be incorporated in the wall of a furnace chamber and having a well extending into the element from the side thereof which is outermost when the element is incorporated in said wall, and having a portion of the wall of said well at a distance from said side shaped to provide seats at different distances from said side, each adapted to receive a corresponding separately formed part of refractory material forming a relatively thin wall between the well space at the outer side of the seat and said chamber, the

outer end portion of said well being adapted to.

pass heat rays to a radiation pyrometer for measuring the temperature of said thin wall, one such part being normally seated in the corresponding putting said part in place in said pa sage.

7. A pyrometric element of refractory material adapted to be incorporated in the wall of a furnace chamber and having a well extending into the element from the side thereof which is outermost when the element is incorporated in said wall, and having a portion of the wall of said well at a distance from said side shaped to provide seats at different distances from said side, each adapted to receive a corresponding separately formed part of refractory material forming a relatively thin wall between the well space at the outer side of the seat and said chamber, the outer end portion of said well being adapted to pass heat rays to a radiation pyrometer for measuring the temperature of said thin wall, one such part being normally seated in the corresponding part and having an integral portion at its outer side adapted for detachable engagement by a manipulating element used in putting said part in place in said passage.

8. A pyrometrlc element of refractory material adapted to be incorporated in the wall of a furnace chamber and having a well extending into the element from the side thereof which is outermost when the element is incorporated'in said wall, and having a portion of the 'wall of said well at a distance from said side shaped to pryovide seats at diflerent distances from said side, each adapted to receive a. corresponding separately formed part of refractory material forming a relatively thin wall between the well ,space at the outer side of the seat and said chamber, the outer end portion of said well being adapted to pass heat rays to a radiation pyrometer for measuring the temperature of said thin wall, one such part being normally seated in the corresponding part and having an undercut mtegral'portion at its outer side adapted for detachable engagement by a manipulating element used in placing said part in said passage.

ANKER E. KROGH. 

